Driving and stopping mechanisms



*Filed May 7, 1957- Sept. 8, 1959 F. ASHWORTH ETAL 35 DRIVING AND' STOPPING MECHANISMS 3 Sheets-Sheet 1 Inven fora Fed Ash worzh 17569 05, 1?. Jqcznn i Hi Spt. s, 1959 F. ASHWORTH ET AL 2,903,114

DRIVING AND STOPPING MECHANISMS Filed May 7, i957 3' Sheets-Sheet 2 fik ven fors 2,903,114 Patented Sept. 8, 1959 States Patent Ofiice erly, Mass., .assimiors .to United Shoe .Machinery Corporation, Boston, Mass.,.a corporation of New Jersey Application May 7, 1957, Serial No. 657,668

7 Claims. (Cl. 192-146) invention relates to improvements in driving and stopping mechanisms which are particularly suitable for transmitting power to a heavilyconstructed shoe sewing machine, and *forstopping-su'ch amachine'at a predetermined point :of its sewing cycle.

In some respects, the driving and'stopping mechanism -'embod-ying the-present invention is similar to a prior one disclosed in a co-pending application for United States Letters Patent No. 543,428, filed October 28, 1955, in the names of the present inventors. Both the prior and the present'drivingmechanisms include shafts, which may be driverreither through h'igh speed clutches *orthroug'h lowspeed clutches selectively engageable in responseto movements of control trcadies. In each mechanism the lowspeed clutch is engaged temporarily to provide braking action when it is desi-redto stop after operating at high speed". 'The prior mechanism includes a device "for sens- 'ing the "braking action of the low-speed clutch and for delaying initiation ofthe final stage of the machine stoppingcycle until after the braking effect has reduced the 'speed of the 'd'riven'shaft to that of the low speed-clut'ch. The duration of thestopping period of the prior mechanismis therefore variable in accordance with themomenturn of the machine parts and the braking -action-of the low-speed clutch. In addition to variations in the duration of successive stopping periods, which may under certain circumstances assume objectionable proportions, the prior driving andst'opping mechanism is also both complex andex-pens'ive to construct.

It is' accordingly an object of the present invention to provide a more simple mechanism "than has heret'ofore been available for driving and stopping heavily constructed sewing or other machines having similar driving and-stopping requirements. it is another object to provide such a mechanism in which the need for sensing the braking action of a low-speed clutch during a stepping cycle is completely eliminated. 'Yet another object is to provide a driving and stopping'mechanism in which a braking force is applied to the driven shaftduring a fixed angle of rotation for stopping the mechanism in a predetermined angular positionofthe driven shaft and with minimum danger of damage due to excessive shock. It is still another object-to provide'an improved-driving and stopping mechanism of the type-referred to which may be adjusted for variations in machine driving and stopping requirements and for compensation of wear' in the con- 'trol connections. Another objectis to provide a machine driving and stopping mechanism, which, although relatively economical to manufacture, is more reliable and accurate in operation than mechanisms heretofore available.

Inthe achievement of the foregoing objects, an important' feature of the invention relates primarily to" a nonyielding disconnectible connection interposed in a driving and stopping mechanism between the control 'treadle and a toggle, the movement of which toggle regulates the engagement and disengagement o'f'thehighand low-speed clutches. *Asin the prior mechanisms, the'toggle is connected to 'a driven memberof each of the two clutches in such a way that the low-speed clutch is engaged when the'links'ofthe toggle are substantially alined. The highspeeclclutch is engaged when the links are substantially 'misalined, and both clutches are disengaged when the links are arranged in either of two positions in which they are neither substantially alined nor substantially misalined. The novel disconnectibleconnectionbetween the treadle'and the central joint of the toggle in the present mechanism comprises a latch, which when engaged causes the position of the toggle to 'vary exactly in accordance with 'that'of the control treadle and when released allows the control treadle to be moved without imparting a corresponding motion to the toggle. The independent motion of the treadle is utilized in stopping the mechanism for performing certain necessary auxiliary functions by means 'offelements connected to the treadle'without at the same time-causing motion of the toggle.

"Sincethe speed at which a shoe sewing machine is operated must be accurately regulated according to positioning'movements imparted to a shoe being presented to the machine, the latch of the invention offers a valuable advantage in driving and stopping mechanisms intended for use in combination with shoe sewing machines. In sewing about'the contour of a shoe the'straighter portions of "the scam may be inserted at high speed but in those parts of the shoe having more abrupt curvatures the sewingsp'eed must be substantially reduced for accurate inse'rtion of 'the' seam. An accepted method of regulating the speed of a sewing machine is by causing variable relative slippage between the driving and driven members of a clutchb'y changing'the pressure of engagement between the members. Because the latch of the present mechanism provides a positiveconnection for movement in two directions between the treadle and the toggle, a more quickly responsive control is possible than in the .prior driving and stoppingmechanismin which the connections between the treadle and toggle include'two arms one overlying the other. The arrangement of the prior mechanism provides positive control of the high-speed clutch when the treadle is depressed for increasing the contact pressure between the driving and driven member of the "high-speed clutch but relies upon a spring for reduction of the contact pressure in response to releasing of the treadl'e by the machine operatorsfoot. By reason of the spring force the overlying arms in the prior mechanism may separate momentarily as the treadle is released to reduce the contact pressure so that the speed is reduced only after an objectionable delay. The operators sense of reaction from treadl'e movement is also absorbed by the spring, thus increasing the difiicul'ty of intelligently controlling the machine. Because a momentary lag is possible between treadle movement and consequent change in clutch member contact pressure and because a yielding connection does not provide an operator with a fully satisfactory reaction to foot pressure, the nonyielding connection acting positively in two directions in the present mechanism is superior to the prior one-way connec tion, especially for use in conjunction with heavily constructed sewing machines requiring positive stopping in a predetermined position.

Another feature of the invention relates to a timing or lock-out, the operation of which ensures engagement of the low-speed clutch through a fixed angle of rotation of the driven shaft before the latter is stopped in a predetermined position. To avoid undue shock in stopping, the angle through which the driven shaft rotates at low speedis chosen to assure sufficient braking action before engagement of a pair of shaft stopping impact members. Another result of the timing lockout is that the speed of the driven shaft is reduced gradually, first by a variable free coasting period before the low-speed clutch is engaged upon the actuation of the timing lockout and then by the braking action of the low-speed clutch. As a result of the consequently decreased momentum during the variable free coasting period the clutch members have a longer useful life than would otherwise be possible and a smoother stopping action is obtained. Still other features relate to the use of an auxiliary operations arm actuated during the stopping cycle for performing certain functions, such as raising the presser foot of a sewing machine with which the driving and stopping mechanism may be employed and a detent for maintaining the lowspeed clutch in engagement until the auxiliary operations arm is actuated in stopping.

The foregoing objects will be more full appreciated and the various features of the invention will be more fully understood from the following detailed description of an illustrative embodiment, taken in connection with the accompanying drawings in which:

Fig. 1 is a sectional view from the right side of a portion of a sewing machine equipped with a driving and stopping mechanism embodying the features of the present invention;

Fig. 2 is a perspective view looking from the right front of the driving and stopping mechanism shown in Fig. 1 with some of the parts omitted for clarity;

Fig. 3 is a detail plan view of clutch control connections incorporated in the driving and stopping mechanism;

Fig. 4 is a view in perspective showing an auxiliary operations arm and its actuating means;

Fig. 5 is a view in right side elevation and partly in cross section of the auxiliary arm actuating means shown 1 The apparatus embodying the present invention isshown in Figures 1 and 2 as a readily removable driving and stopping mechanism, especially suitable for heavy sewing machines and other machines having similar driving and stopping requirements. Like the prior mechanism of the above-identified co-pending application, the present mechanism, by being readily removable, provides greater facility for repairs, adjustments, and replacements. The mechanism is shown in the drawings connected to a shoe sewing machine of the McKay type, which is operated through a horizontal shaft 10 and an oblique shaft 12 by means of a horizontal shaft 14 driven by the driving and stopping mechanism. The driven shaft 14 is splined at its forward end for coupling to a gear 16, which in turn drives the shafts 10 and 12. Since the sewing machine comprising the shafts 10 and 12 forms no part of the present invention, it will not be described further in the present application but it may be fully understood if need be by reference to the co-pending application.

The present mechanism like the prior mechanisms includes highand low-speed clutches having driving members 18 and 20, respectively, surrounding the driven shaft 14. The driven shaft 14 is rotatably supported in a housing or frame 22 very similar to that of the prior mechanism. Since the arrangement of the clutch driving members and of the driven shaft 14 is exactly like that of the prior mechanism, it will not be described in detail but reference may be made to the co-pending application for a fuller understanding.

Because the need for a speed sensing device has been eliminated, as will be explained, the driven members of the present clutches, although similar to those of the prior mechanism, have been considerably simplified in their mountings. Thus, the high-speed driven member comprises a wheel 24 having a peripheral facing 26, fixed together with a low-speed wheel 28, having a peripheral facing 30 both secured to a sleeve 32 splined to the driven shaft 14 in a manner permitting the sleeve to be moved axially on the latter. The action of the driven clutch members when engaged with their respective driving members is the same as in the prior mechanism, except that the low-speed driven member 28 is not free for limited rotary movement relative to the sleeve 32 but directly causes rotation of the latter and of the driven shaft as soon as the facing 30 engages the driving surface of the lowspeed clutch member 20.

Engagement and disengagement of the clutches is controlled by the position of a toggle comprising links 34, 36 having a central joint in the form of a pivot 38. The toggle and its connections to the sleeve 32 are exactly the same as in the prior mechanism and include a yoke 40 pivotally coupled through interposed elements to the end of the link 36 remote from the pivot 38. The forward ,end of the link 34 is pivoted on a square-headed stud 42 (Fig. 2) slidable in a counterbored opening of a lug 44 integral with the frame. As in the prior mechanism the stud 42 is pressed rearwardly by a compression spring 46 and its rearward movement is limited by a pair of check nuts 48.

In accordance with one of the features of the present invention we have provided a disconnectible connection rather than a one-way actuating connection between the control treadle and the central joint of the toggle. The disconnectible connection includes a latch 50 pivoted at the rearward end of one of the arms of a twoarmed lever 52 pinned to a horizontal shaft 54, which is rotatably supported in upstanding ears integral with the frame 22, the latch being shiftable in an arcuate path with the lever 52. The other arm of the lever 52 is pivoted at its rearward end to a generally vertical link 56, the lower end of which loosely surrounds the pin 38, which forms the central joint of the toggle. The latch 50 is urged by a spring 55 into engagement with a finger 5 8 fixed at the rearward end of one of the arms of a three-armed lever 60 rotatable on the shaft 54, the said arm of the three-armed lever 60 having a lateral projection 66 underlying the latch carrying arm of the lever 52. When the latch 50 is engaged with the finger 58 the levers 52 and 60 are coupled by the latch and the projection 66 for conjoint movement, and the relative positions of the toggle links are determined by the position of the lever 60, which is, in turn, connected to the control treadle. When the latch 50 is disengaged the lever 60 may be moved downwardly away from the lever 52. A second rearwardly extending arm of the lever 60 is connected by means of an irregularly shaped link 62 to a lever 64 (Fig. 1) fulcrumed on the frame 22 and coupled to a treadle 65 in much the same manner as that of the prior mechanism.

With the parts positioned as illustrated in Fig. 2, the latch 50 is held out of engagement with the finger 58 of the lever 60 by the engagement of a projection 70 integral with the latch, with a stationary stop member 68 adjustably fixed upon the frame 22. The projection 66 engages the under side of the lever 52 forming a one-way connection so that upon depression of the treadle and counterclockwise movement of the lever 60, the lever 52 is caused to move similarly because of the engagement of the projection 66 therewith, whereupon the projection 70 moves out of engagement with the stop member 68 and the latch is moved by the spring 55 into latching engagement with the finger 58. But in stopping the machine it will be obvious that after release of the latch 50 further raising of the treadle imparting a clockwise movement to the lever 60 will have no effect on the position of the lever 52, the one-way connection being effective only when the lever 60 carrying the projection 66, when in engagement with the lever 52, is moved in a counterclocle 55 wise directionra sizseen inrEigi. 'L'Ihu,:theileVers:52aand 60 are connected for unitary movements in either=:direcitioni by f the projection :.'66 iandtbylthe aengagement I of the dateh 5 0 'withi.thezfingers58,lwhich:forms -a;disconnectible 'con-nection.

Whilethei latch.:isiengagedx.the *axial force "bringing the aclutch members into engagement is determined :directly :by the .=position: of the :controlwtreadle; since the 'leversx52 and-60: then. moveztogether. 'Whentthe? treadle is released the projection .70 on the 1 latchrSl): contacts-the stationary astop :mernoer $.68 for :disengag-ing tthe Elatch .from the "fingeriSS.

i'The: mechanism -is brought'to'. asstop imapredetermined rangularposit-ion of thedriven shaft .14 by engagement f impact :stop :members including "a buffer lever 72 zmountedmn thetdriven :shaftzand a'stop roll .74 which -a'cts1as1a:stationarysstoprmember. During the operation ofthe mechanismtthe roll i74rzis maintained out of the :pathof: therbuffer lever .as along? as .the latch.-50 of the dis- ;connectible :connection; remains engaged-as will be here- :inafter (described.

in order to11minimi2e shocksaccompanyingithe engagement Iof :theirnpact stop :members the :low-speed clutch -is1engaged; for .a 'r'ixed periodtofrtime after the 1 high-speed iClILlIChis disengaged so that it will act-as a :brake upon the zdiiven shaft before the impact stop-members come-into tcontact wi'th each other. Before .the:period of low speed :braking starts the :driven shaftl4zmayrotate freely with- 'out being. driven-shy .eithertclutch. vTheastart of the braking period is controlled by a timing pawl which'includes aa'pawl: lever 76 pinnedto one end of .ashaft 78 rotatable inial-lug integral withthe frame .22. Atwo-armed lever -t80.-is pinnedtoithe other end cofthershaft 78 and is connected'byalink 82'to one.arm of a -V-shaped.lever 84 .pivotedon :the frame 22. The lever-84 carries at the 'sextremityof' itsother arm. at follower: roll =86 malntalned in 2' engagement with a .cam :88, .fixed upon the .shaft The roll is pressed against the cam 88 by a tension--spr1ng "$10.2 stretched between .a free. arm of. theilever -80 and an rancher point-onthez'frame.

Tonenable-an operatorztozfeel .thereactionon his foot was it rests ton'the control.treadle-65 before thebraking :pcriod-starts, thevlatch SOdsrheld temporarily in engage- .ment with the finger 58, aftertthe control .treadle 1s par- :tiallycreleased. Thistemporary holding is-aocomplished lby;engagement.ofthepawl lever 76 with the front face :of an arcuate block-9'2 adjustably fixed upon the lower tend oftaadepending arm :94gpinned .to the shaft 54. The .icamvfis'is formed-with a periphery concentric with the 4.:axis1of the -shaft*14 except for a projection 96, sothat -.the: paw1 lever F76 remains motionless except when the :projectionrengages the follower roll 86. 'Whenthe treadle iis released "for stopping themachine, clockwise movesment1oftthe .arm94 is arrested by-engagement of the iforwardface"of'the block-92 withthe pawl lever 76 thus gpreventing .the .latch' 50:from "becoming disconnected and ::also :delaying sengagement z-of the --low-speed clutch until wthe camvprojection 9.6 .causesthepawl-lever 76 to move +outn'ofstheipath' ofxthe arcuateiblock. It1is at this time ithatilthe driven shaft 14- rotates rfreely. :Theprojection 596 isqorientedron the shaft- 14 to; engage the follower roll :SGrapproximately' 180 :of shaft rotation before thermlpactistopmenibers comeinto ZCOIltfiCLTHS shown n Plg. I2. r-mDuringtthe rnajorwportion of this 180 rotation the low-speed clutch is effective to-reduce the speed of the Q'drivenshaft -14. During the T final portion of this 180 irotation -thetdriven shaft rotates-under the force of its tovtmmomentum so that theengagementofthe stop mem- .bers occurs witlra minimum of-shock. It will also be .-appreciated that if, for example, the control treadle is :released when thebuifer lever .72 is less than 180 from the: position of thestop roll 74, the lever 76 engages the "block" 92thereby keeping both'clutches'disengaged until "the projec'tion96 causes the "block 92 to'be released. Thusg thwshaft=14*revolves' approximately 180 if the t6 projection 96 .is in contact :with the followerroll -.at:th time fthe:treadlerisxeleased,zbut the stopping cycle: includi-ing alvariablea coastingsperiod may-he; extended by almost a. complete revolution .oftthe drivenzshalft ifithe -sprojeetion has just moved J out *ofzcontact with the follower sroll :at

the time that.the 'treadle is released.

:When the:block:92:isireleased by the lever.76,:limited 1 movement .is imparted i to .the;central joi-ntoftthe control toggle by. the forceof a spring'981 Eigs.:l .and 3 cstretched bet-weenlthe frame .221and az pivotpin 100 which forms the connection betwecnthelink 56:.and'1theleverfi2. :The movement of the centraljoint:iszarrestedbefore thertoggle assumes the position depicted. in:Figs. 1.:andx2 by1a lockout= latch .102, shownin .Fig. "4, which engages 'a.-suitable projection on "the 'togglelink T34. 'Theilimited movement of the toggle'linksscauses thelow-zspeed .elutchto engage. During .this limited movement :aftertthe .low- :speed clutch has become.engaged,tthe'latch;50 is released by engagement of :the :projection '70 "with .the'fixed :stop :member 268 and 1 thereafter "the :lever 60 :is moved 10. its clockwiseextreme, asshown in Figs; 1 and 2,by:a'ispring (not shown) connectedxtozthe control vtrea'dle as'in the prior mechanism. Since 'itheilatch '550 ;is released after zthe low-speed clutch :becomes :engaged, the present arrangement enablesan. operator .to feel, by. means oftreadle reaction, thetime 'of 'engagementof either..clutch. 'Such movement of the lever6ll after release of ithe latch '50 occurs without affecting the :positions of the control toggle or the lever'52,-'sincerthe'-levers-52 and 60 are then independent.

Acamsegment flit-t formedintegrally with a forwardly extending arm of the lever 60 normally posit-ions the stop 101174 out of thepath: of the buffer lever 72 during operation ofithe mechanismandtperrnits movement of the roll into the path of the lever forbringing themechanisrn to a stop. *Formaintaining"thestop roll'7'4 out of the path of the .bufferrleverthecam segment engagesa .follower roll I106 :rotatable'at'the end :of a rear-wardly extendingsarm of: a leverfl tl8 pivoted on a stud-110 which is fixedly supported in:the 'frame. The'stop roll 74-is rotatably mounted on .adepending arm of a lever 112, the upper end. of which is formedinto a gear segment. The. lever 112 is fulcrurned on a transverse stud 114m at pendant. arm 11.6 integral with an inner sleeve'118-surrounding ashaft 120. Thearm 116 is pinned to'the .shaft 120, which is rotatablymounted'in a pair'of'opposed ears integral with the frame. The inner sleeve is surrounded by an outer sleeve I22having its forward end formed with rack teeth- Whichmesh with thoseof the gear segment onthe lever 112. 'The outer sleeve 1'22 is axially slidable ontheinner sleeve and whenin its-most rforwardposition causes the stop roll 74 to assume the "position shown'in dot and fdash-lines in Fig. 5- in which position the roll lies out of-thepath of the' buffer lever. A spring 124 compressed between'the shaft and an .toffsetmember lzta fixed to therearward end of theouter .sleeve biases the latter for rearward movement. The ioutersleevell22 is formed at its.forward end with alateral .projectionihavinga vertical slot 128, which isengage'd by a roll 138 rotatably mounted on a depending armof the lever 1198. Whenthe follower roll 186- isengagedby the'cam'segment 18.4,: the outer sleeve 1 22 is thus-maintained in its. forward positionagainstthe bias of the compression spring .ll24Jand the st/op-roll'74 -is thus-kept out of the pathofthe huifer'lever 72. i-Whenthe arm-604s freed-:by therreleaseof'thelatchSt) toturn in such a .manner-that the cam segment 1=04vmoves'out of engage- -.ment with the IOllf106,fth8 s1eeve1122 is urgedrearwar'dly by the spring 124 .andthe stop :roll '74 is consequently thrustinto the vpathv of itheqbuifenlever.

Before the driven shaft-.of'the driving and stopping mechanism is stopped-certain auxiliary-motionsmay be necessary in the .machinezwith which the mechanism 'is :associated. Thus, in theasewing-"machine fragmentarily ashowninFig. sl;it-.is.:advantageous to raise 'the presser foot and to alter the timing of the thread locks before mounted on the shaft 120 adjacent its rearward end.

The sewing machine presser foot is raised when the machine is stopped by clockwise rotation of a shaft 136 journaled in the sewing machine frame. The arm 132 is moved by mechanism to be described, and the movement of this arm is imparted to the shaft 136 through connections including a bell crank 138 fixed to the rearward end of the shaft. A generally vertical link 140 is pivotally connected to the bell crank 138 at its upper end and at its lower end to the extremity of the arm 132 remote from the shaft 120. The connections for changing the timing of the thread locks include a rod 142 slidable in the machine frame which, in the position shown in Fig. 4, presses forwardly against a lever 144 to change the thread lock timing as the machine is being stopped. Connections to the shaft 136 for operating the presser foot and the arrangement of the thread locks are fully described and shown in the above-identified co-pending application to which reference may be had for a fuller understanding. The rod 142 is engaged at its rearward end by a cam surface on a forwardly extending arm of a lever 146 fulcrumed on a stud 148 fixedly supported in the driving frame. A rearwardly extending arm of the lever 146 is coupled to the arm 132 by a short vertical link the lower end of which loosely surrounds a pin on the lever and the upper end of which is pivotally connected to the arm 132. A spring 152 is stretched between an anchor on the driving mechanism frame and a pin extending from a collar 154 adjustably fixed on the rod 140. The spring 152 and the presser foot spring, which urges the presser foot into contact with the Work while the machine is operating, are both effective in urging the rod 140 upwardly from the position shown in Fig. 4.

For imparting the necessary motion to the arm 132 before the rotation of the driven shaft is arrested, the stop roll 74 engages the periphery of a cam 156 upon which the bufier lever 72 is mounted (Fig. 2). The cam 156 which is fixed to the driven shaft has a contour which includes a lobe extending approximately 45 in advance of the buffer lever 72 for imparting to the roll 7 4 a motion away from the axis of the driven shaft. Movement of the roll 74 is transmitted through the lever 112 and the shaft 120 to the auxiliary arm 132, causing the latter to assume the position shown in Fig. 4 before the rotation of the driven shaft is stopped. The block 134 upon which the arm 132 is mounted is formed with a slot, the ends of which embrace the opposed edges of the offset member 126 so that the motion of the arm is also coupled to the outer sleeve 122 without imposing undue stress upon the rack portion of the outer sleeve.

As the butfer lever 72 approaches engagement with the stop roll 74 the arm 132 is latched in the position shown in Fig. 4 and the roll 74 is no longer urged into engagement with a periphery of the cam 156. As the arm 132 is approaching its latched position the look-out latch 102 is released, thus permitting disengagement of the low-speed clutch a sufficient angular distance in advance of the engagement of the stopping members so that the engagement occurs with a minimum of shock.

While the low-speed clutch is engaged, the latch 102 is biased into engagement with the projection on the link 34 by a spring pressed plunger 158. Connections for releasing the latch 2 include a shaft 160 to one end of which the latch is pinned. The shaft 160 is rotatable in the frame and carries fixed. The shaft 160 is rotatable in the frame and carries fixed at its other end an arm 162 having an adjusting screw 164 threaded into an opening near the distal end of the arm. The screw which is locked in position by a check nut 166 engages a plate 168 fixedly secured to the plate 134 and the arm 132.

- The screw 164 is adjusted to cause release of the latch 8 102 before the arm 132 reaches the position shown in Fig. 4.

A latch is provided for maintaining the arm 132 in the position of Fig. 4 while the mechanism is stopped. The latch includes a lever 170 fulcrumed at the lower end of a bracket 172 pendantly supported on the frame as shown in Fig.7. At its upper end the lever 170 is provided with an adjustable angle iron latching member 174 (see also Fig. 8). The member 174 is retained upon the lever 170 by screws 176 which pass loosely through a slot in the member and are threaded into the lever. The vertical adjustment of the member 174 determines the latched position of the arm 132 while the mechanism is at rest. The lever 170 is urged toward its latching position by a spring 178 stretched between a short arm of the lever extending below its fulcrum and a depending extension of the bracket 172. The movement of the arm 170 under the bias of the spring 178 is limited by an adjusting screw 180 threaded in the depending extension of the bracket and retained by a check nut 182. While the mechanism is in operation the member 174 is in contact with the forward edge of the plate 168. During the stopping of the mechanism the arm 132 is actuated, as already described, and as its outward end is depressed to a position slightly lower than that shown in Fig. 4, the edge of the plate 168 moves out of engagement with the member 174 thus allowing the arm 170 to be moved by the spring 178 to bring the member 174 into underlying or latching engagement with the plate 168.

Before the machine is started the member 174 is moved out of latching engagement with the plate 168 by a finger 184 (Figs. 6 to 8) bolted to the offset member 126. After release of the latch by the finger 184 and during subsequent operation of the driving and stopping mechanism, the member 174 is kept out of latching engagement with the plate 168 by contact of its rearward edge with that of the plate.

A fuller understanding of the driving and stopping mechanism will be obtained from the following brief description of a starting sequence beginning with the component parts initially in the positions shown in the drawings. When the control treadle is depressed the link 62 rises causing the cam segment 104 to engage the roll 106 (Fig. 2). As a result of this engagement the outer sleeve 122 slides forwardly on the shaft 120 and by engagement of its rack portion with the gear teeth of the lever 112 causes the roll 74 to move rearwardly out of the path of the buffer lever 72. After disengagement of the stopping members the lateral projection 66 of the three-arm lever 60 engages the underside of the latchcarrying arm of the lever 52 causing the latter to pivot in a counterclockwise direction as seen in Fig. 2. During the pivoting movement of the lever 52 the toggle links 34, 36 become alined sufficiently that the low-speed clutch is engaged. As the control treadle is further depressed the latch-bearing arm on the lever 52 is rotated further in a counterclockwise direction until the projection 70 of the latch 50 is out of engagement with the stop member 68 and the latch is moved by the spring 55 into engagement with the finger 58. Thereafter the relative positions of the toggle links and consequent force of engagement of either the high speed or low speed clutch is controlled by the treadle since the levers 50 and 52 are latched for movement together.

In bringing the mechanism to a stop the control treadle is released causing the link 62 to move downwardly and the lever 60 to be pivoted in a clockwise direction as seen in Fig. 2. Before the latch 50 is released by engagement of its projection 70 with the stop member 68, the pivotal movement of the lever 60 is temporarily arrested by engagement of the forward face of the arcuate block 92 with the pawl lever 76, which engagement also delays the engagement of the low-speed clutch. The

9 :tmoieetion $6 1en:; e;. .am:.58 112v eng s ngeth .1 ol :56 refle t :i he re eas 39 tth i'l ver 9.2 ;.an. :.:.60 for limite nnQvemen ;tsgethertinlaelc kwis d r c ion.assh Wni :F'g. 32. Dnring theflimitedmovement of the leversithe as already described. :Duringthe period .of low-speed celuiqhengagement ;the..toggle links .are maintainedtgen- ;.;.erally;.in=;alinement by the latch-1(l2,.shown.inFig.4. '..AS -,.the.shaft;1-4 continues .to. be driven :by;.-the; low-speed clutch after engagement of the stop roll with :the cam ';]i56, .movement .toward the .position shown in. Eig. 4 is .impartedto the arm 31:32 ;,by thelcontour ofthecam. 4A8 the :arm 132 approaches .the position shownsin 71F ig. .4 n-thetscrewlfitlisengaged by the plate 16810 cause release... of ;the :latch.:102, lwhich release is accompanied by -.disengagement of :the lowfspeed. clutch and followedrby -..a coasting period preceding engagement of the stopping -members. As.;the .movement of the arm 132 causes the trodtldil to assume .a position-slightly below thatshown 1. in.. Fig. 4, the latching member 174 isswung under the aplateylds bythe spring-1773 and thearm 1332 is thereafter -1atchedinthe-position shown in Fig. 4. The=buifer lever :"'72-.then coasts into shockless engagement with thestop -rolli'Z4-for arresting the rotation of the shaft 14in the desired angnlar position.

.a=way. that no serious damage can result to the. parts of athe mechanism in the-event of 'a malfunction allowing thestopping members to engage with greater than normal aimpact. i-For this purpose-the bulfer'lever ispivoted ona :Jing position by a compressionspring 188 -with-an arm of *the buffer lever ,in engagement with an integral-lug of .the. cam 156. In theevent of excessive shock upon engagementof thestopping-membersthe spring 88, which isguided by ascrew threaded in the lug, -is. compressed "as vthe buffer lever pivots inacounterclockwise direction 4(Fig52) toescape the engagement with the-roll*7-4. The only/effect of this :escape is an added revolution of the driven shaft since the spring 188 EXGItSSUfllCleHF-fOI'CC*tO prevent escape of the buffer lever at an impact force level which may be safely withstood by the stop-ping members.

Having thus described our invention, what we claim as ;new and .desire .to secure by Letters Patentof-the :United States is:

'1. A drivingand stoppingmechanism for a heavily constructed .sh'oe solesewing machinerequiring accurate control at either of two speeds at the option of an operator, said mechanism having a frame, driving members, a driven shaft, highand low-speed clutches between the driving members and the driven shaft, a yoke for engaging either of the clutches for extended periods to rotate the driven shaft at either speed, a treadle for actuating the yoke, a pair of toggle links coupled at one end to the frame and at the other end to the yoke, and arranged to cause the low-speed clutch to be engaged when the links are moved to positions of substantial alinement and to cause the high-speed clutch to be engaged when the links are moved to positions of substantial misalinement, means connecting the treadle to the toggle links at their central joint, said means including one-way connecting means between the treadle and the central joint of the toggle links for moving the latter in one direction only to a position of substantial alinement in response to movement of the treadle in a corresponding direction, in

peed .clutch ;;b.ecornes engaged n here.a.f er the Thebuifer lever 72 is mounted on-the cam'1-56 insuch 3:35

.zstud.:186and.yieldingly maintained in-its-stop roll engagcontrolat eithenof two-speeds at theoption of.an.-operator, said -mechanism having.a"frame,.driving members,-.a driven shaft, highand .low-speedclutches betweensthe driving members. and the driven.shaft,=a-.yokeifor;engagring either oftheclutches for extended. periods-totrotate .cthe driven shaft at either speed, a.;treadle ifOI' actuating the yoke, a pair of toggle'links connectedattone endrto the frame and at theother end to.the.yoke,.and arranged to cause the low-speed clutchtto.ebe;engagediwhen t the toggle links are moved .to .positions... of substantial :alinement and ;to. cause the .high.speed.clutch...to beengaged when thevtoggle. linksare moved to positions.of.substantial .misalinement, ,means .connecting the :treadle 1 tto tthe tqggle links at theiricentral'ijoint, said :means including arms of levers anda one-.wayconnection between ithe warms, one .of whiclrlevers is actuated byzthe :treadlmand the other of .whichactuates.thecentral :joint ofr'theetoggle links for moving the latter .in one. directiomonly to a position of substantial alinement .in response .to movement -of the treadle ina correspondingdirection, in combination with a latch operative in response .to movement'of the treadle throughout azportion of its range .for..locking .the lever arms for conjoint movement ;.to.-cause operation ofthe driven shaft byeither the high or .lowespeed clutch according to :the positionof the treadle;throughout;,said portion of the range, .anidmeansioperative in .responseuto movement ofthe treadle beyond saidportion of its range .for disconnecting the latch to permit movementof :the

treadle. in one direction independently .ofsaid .toggle.

.3. A drivingand stopping mechanism for controlling the speed. of operationofa machine. and .forsbringingrthe machine to rest .with its .partsin predetermined positions, said mechanism havinga frame,.d;riv.ing member a :driven ;shaft, high- .and..low.-speed clutches between :the driving ,-members andthedriven shaft, .ayoke for; engaging :the clutches to rotate the driven.shaft,.a treadle for .actuating the yoke, a pair of toggle links connectedatoneend to -,the iframe .andat thejother end .to theyoke, .andaarranged to cause thexlow-speed clutch .to lbe-engaged-twhen ithe toggle links aremcved to ,positionsof-substantial :aline- .ment and ;to.cause the high-speed clutchto "beuengaged when. thetoggle links are movedto positions oftsubstantial alinement, means. connecting :the treadle .to the .toggle 'links at their central joint, said meanslinclud l .aioneway connection between the treadle and-thejcentral J'Qint ,of the;:toggle links for moving the latter to a position .of substantial alinement .in response to movementof the treadle, in combination with means for locking. the-.-.0.neway connection for conjoint movement of the treadle and the toggle in two directions while the driven shaft is being rotated by either the high or low-speed clutch and for disconnecting the connection for movement of the treadle in one direction independently of the toggle, further movement of the treadle after disconnection of the connection imparting no additional corresponding movement to the toggle, and a lockout actuated by the driven shaft to hold up disconnection of the connection until a predetermined position of the driven shaft is reached.

4. A driving and stopping mechanism for controlling the speed of operation of a machine and for bringing the machine to rest with its parts in predetermined positions, said mechanism having a frame, driving members, a driven shaft, highand low-speed clutches between the driving members and the driven shaft, a yoke for engaging the clutches to rotate the driven shaft, a treadle for actuating the yoke, a pair of toggle links coupled at one end to the frame and at the other end to the yoke, and

arranged to cause the low-speed clutch to be engaged when the links are moved to positions of substantial alinement and to cause the high-speed clutch to be engaged when the links are moved to positions of substantial mis- -alinement, means connecting the treadle to the toggle links at their central joint, said means including a oneway connection between the treadle and the central-joint of the toggle links for moving the latter to a position of substantial alinement in response to movement of the treadle, in combination with a latch for locking the oneway connection for conjoint movement of the treadle and the toggle in two directions while the driven shaft is being rotated by either the high or low-speed clutch, and stationary means engageable by the latch for shifting the latch to its unlocked position when the treadle is released.

5. A driving and stopping mechanism for controlling the speed of operation of a machine and for bringing the machine to rest with its parts in predetermined positions, said mechanism having a frame, driving members, a driven shaft, highand low-speed clutches between the driving members and the driven shaft, a yoke for engaging the clutches to rotate the driven shaft, a treadle for actuating the yoke, a pair of toggle links coupled at one end to the frame and at the other end to the yoke, said toggle links being operative to cause the low-speed clutch to be engaged when the links are moved to positions of substantial alinement and to cause the high-speed clutch to be engaged when the links are moved to positions of substantial misalinement, in combination with a disconnectible connection between the treadle and the central joint of the toggle links for moving the latter toward and from positions of alinement upon operation of the treadle while the driven shaft is being rotated by either the high or low-speed clutch, means for disconnecting the connection to permit movement of the treadle in one direction independently of the toggle, a lockout effective to hold up, until a predetermined position of the driven shaft has been reached, the movement of the toggle links toward a position of alinement and the disconnection of the connection, an auxiliary operations arm, means for actuating the auxiliary operations arm including a cam on the driven shaft and a stop roll, and a detent for maintaining the low-speed clutch in engagement until actuation of the arm is substantially completed.

6. A driving and stopping mechanism for controlling the speed of operation of a machine and for bringing the machine to rest with its parts in predetermined positions, said mechanism having a frame, driving members, a driven shaft, highand low-speed clutches between the driving members and the driven shaft, a yoke for engag ing the clutches to rotate the driven shaft, a treadle for actuating the yoke, a'pair of toggle links coupled at one end to the frame and at the other end to the yoke, said toggle links being operative to cause the low-speed clutch to be engaged when the links are moved to positions of substantial alinement and to cause the high-speed clutch 12 to be engaged when the links are moved to positions of substantial misalinement, in combination with a first lever connected to the treadle, a second lever connected to the central joint of the toggle, a releasable latch shiftable along an arcuate path and pivoted on one of said levers for coupling the levers together to move the toggle links toward and from alinement upon operation of the treadle, a fixed latch release member in the path of the latch to release the second lever for motion independently of the first lever after the toggle links are in substantial alinement, a lockout for retarding disengagement of the latch up to an angular position of the driven shaft in advance of its predetermined stopping position, and a second latch arranged for maintaining the low-speed clutch engaged after release of the lockout up to an angular position of the driven shaft sufficiently near its stopping position to enable the driven shaft to coast to its stopping position under its own momentum after release of the second latch.

7. A driving and stopping mechanism for a heavily constructed shoe sole sewing machine requiring accurate control at either of two speeds at the option of an operator, said mechanism having a frame, driving members, a driven shaft, highand low-speed clutches between the driving members and the driven shaft, a yoke for engaging either of the clutches for extended periods to rotate the driven shaft at either speed, a treadle for actuating the yoke, a pair of toggle links coupled at one end to the frame and at the other end to the yoke, said toggle links being operative to cause the low-s eed clutch to be engaged when the links are moved to positions of substantial alinement and to cause the high-speed clutch to be engaged when the links are moved to positions of substantial misalinement, in combination with the first lever connected to the treadle, a second lever connected to the central joint of the toggle, a releasable latch mounted on one of said levers for coupling the levers together while engaged to move the toggle links toward and from alinement upon operation of the treadle, a fixed latch release member to release the first lever for motion independent of the second lever after the toggle links have come into alinement, said release member being positioned and formed to arrest movement of the second lever in a stop position in which the toggle links cause both clutches to be disengaged, resilient means urging the second lever into the stop position after the latch is released, and oneway connecting means between the levers for imparting movement of the first lever to the second lever before the latch is re-engaged.

References Cited in the file of this patent UNITED STATES PATENTS Oliver Jan. 8, 1929 

